Packaging apparatus and method

ABSTRACT

AN AUTOMATIC PACKAGE WRAPPING APPARATUS OF THE LSEALER TYPE. THE PACKAGES TO BE WRAPPED ARE TRANSPORTED THROUGH THE APPARATUS IN A STRAIGHT LINE ONE BY ONE AND IN SO DOING PASS THROUGH A FILM INVERTING HEAD WHERE THEY ARE SURROUNDED BY A PRE-FOLDED THERMOPLASTIC FILM. THE FILM IS SUPPLIED FROM THE REAR OF THE APPARATUS IN A PREFOLDED CONDITION AND IS BOTH TURNED INSIDE OUT AND REDIRECTED INTO A PATH CORRESPONDING TO THE PATH OF THE PACKAGES THROUGH THE APPARATUS IN THE FILM INVERTING HEAD. ALSO THAT METHOD OF WRAPPING PACKAGES WHEREIN A GEN-   ERALLY U-SHAPED INVERTING HEAD IS PROVIDED, WHEREIN A LENGTH OF LONGITUDINALLY PRE-FOLDED THERMOPLASTIC FILM IS PASSED OVER AND THEN THROUGH SAID HEAD THEREBY TURNING THE FILM INSIDE OUT AND REDIRECTING ITS PATH AND WHEREIN THE PACKAGE TO BE WRAPPED IS PASSED THROUGH SAID INVERTING HEAD THEREBY SURROUNDING ITSELF WITH SAID FILM.

June 8, 1971 F. a. SHANKLIN PACKAGING APPARATUS AND METHOD 6Sheets-Sheet 1 Filed April 10, 1969 INVENTOR FRANK GARRETT SHANKLINATTORNEYS June 8, 1971 F. G. SHANKLIN PACKAGING APPARATUS AND METHOD 7 6Sheets-Sheet 2 Filed April 10, 1969 N QE E Q mm INVENTOR FRANK GARRETTSHAN KLIN ATTORNEYS 3mm 197:1 F. G. SHANKLIN 3,583,888

PACKAGING APPARATUS AND METHOD I Filed April 10, 1969 6 Sheets-Sheet 3as 45 48 F 77 Z K L j 76 49 52 INVENTOR FRANK GARRETT SHANKLIN ATTORNEYS1971 F. G. SHANKLIN 3,583,888

PACKAGING APPARATUS AND METHOD Filed April 10, 1969 6 Sheets-Sheet &

FIG.5

FIG. 6

INVENTOR FRANK GARRETT SHANKLIN BY, 6 W

ATTORNEYS u 8. 1971 F. s. SHANKLIN 3,583,888

PACKAGING APPARATUS AND METHOD Filed April 10, 1969 e Sheets-Sheet 5INVENTOR FRANK GARRETT SHANKLIN BYLw M f m ATTORNEYS un ,8. 1971 F. G.SHANKLIN 3,583,888

PACKAGING APPARATUS AND METHOD Filed April 10, 1969 GSheets-Sheet 6 l 039 LL.

. 1 8}" Q I? '3 S2: 4' L| 6 Q INVENTOR FRANK GARRETT SHANKLIN 'flvrfiw-5W ATTORNEYS United States Patent O US. Cl. 53182 7 Claims ABSTRACT OFTHE DISCLOSURE An automatic package wrapping apparatus of the L- sealertype. The packages to be wrapped are transported through the apparatusin a straight line one by one and in so doing pass through a filminverting head where they are surrounded by a pre-folded thermoplasticfilm. The film is supplied from the rear of the apparatus in a prefoldedcondition and is both turned inside out and redirected into a pathcorresponding to the path of the packages through the apparatus in thefilm inverting head. Also that method of wrapping packages wherein agenerally U-shaped inverting head is provided, wherein a length oflongitudinally pre-folded thermoplastic film is passed over and thenthrough said head thereby turning the film inside out and redirectingits path and wherein the package to be wrapped is passed through saidinverting head thereby surrounding itself with said film.

SUMMARY OF THE INVENTION L-type sealing machines have become quitepopular in recent years, especially for overwrapping a variety ofpackages such as those, for example, containing phonograph records ortoys with a shrinkable thermoplastic film. The L-type sealer employspre-folded film and simultaneously forms a transverse seal and alongitudinal seal with the longitudinal seal located opposite andparallel to the prefolded edge of the film. Normally a hot wire impulsetype sealing means is used so regulated that the wire both severs thefilm and forms a seal on both sides of the severed portion. Thus thefinal transverse seal of one package is the initial transverse seal ofthe next package and a package is formed with each cycle of the sealingjaws.

Normally in such machines the film is pre-folded and passes in astraight line through the machine with the folded edge toward the rearand the free edges toward the front. The package to be overwrapped isinserted from the front between the free edges. Frequently, a shelf-likestructure is provided that extends between the free edges of the film tofacilitate the insertion of the articles to be overwrapped. Some effortshave been made to make such machines automatic, but these have turnedout to be quite complicated due to the fact that the packages are fedfrom the front at essentially right angles to the path of the film; thatthe film must be separated to admit the package and that after beingsurrounded by film the package must move at right angles to its previouspath.

One problem is that a web of a pre-folded film does not maintain itstrack properly when a 3-dimensional package is inserted into it.Essentially what happens is that the film opens in such a way that thebottom layer of the film lays flat under the shelf or table on which thepackage is placed, whereas the top web of film has to wrap around threesides of the package. This obviously would displace the free edge of thetop layer relative to the free edge of the bottom layer. If the packageswere wrapped individually this would be of little importance. But wheremultiple packages are made with a common, through severed, seam betweenpackages, the inaccuracies of the first package tend to multiply in eachsucceeding package.

3,583,888 Patented June 8, 1971 It is the object of this invention toprovide an automatic wrapping machine of the L-seal type wherein thearticles to be wrapped are transported through the apparatus one by onein a straight line. Another object of this invention is to provide meanswhereby the articles to be packaged or overwrapped surround themselveswith film solely through the motion of the said articles through themachine. A further object of this invention is to provide means foroverwrapping articles with pre-folded film which means are essentiallyself-centering. These and other objects of the invention will becomeapparent from the drawing and from the detailed description whichfollows:

DESCRIPTION OF THE DRAWING FIG. 1 is a front perspective view of thepackaging apparatus of the present invention.

FIG. 2 is a top view of the apparatus of FIG. 1.

FIG. 3 is a top view of the film feed and the film inserting portion ofthe apparatus of FIG. 1.

FIG. 4 is a side elevation corresponding to FIG. 3.

FIG. 5 is a side elevation corresponding to FIG. 4 but showing theopposite side.

FIG. 6 is a side elevation corresponding generally to FIG. 5 but showingan alternate film feed means.

FIG. 7 is a rear perspective showing the detail of the operation of thefilm inverting means of the present invention.

FIG. 8 is a front perspective showing an alternative form of filminverting means.

FIG. 9 is a front elevation of the apparatus shown in FIG. 1.

FIG. 10 is a front elevation partially in section showing details of theleft-hand portion of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION The packaging apparatus of thepresent invention indicated generally at 21 comprises a package infeedsection indicated generally at 22, a film unwind and inverting sectionindicated generally at 23, a package insert section indicated generallyat 24 and a sealing section indicated generally at 25.

The package infeed section, indicated generally at 22, comprises apackage infeed conveyor 26 mounted on two rollers 27 and 28 which inturn are mounted on extension 29 of main frame 31. The upper surface ofinfeed conveyor 26 is provided with a pair of parallel guides 32 and 33adapted to cause packages (indicated at P) to follow a predeterminedpath along conveyor 26. Guides 32 and 33 are mounted on U-shaped supportarms indicated at 34 in the case of guide 32 and at 35 in the case ofguide 33, which in turn are mounted in extension frame 29 in such manneras to permit the lateral adjustment of guides 32 and 33 to the desiredposition. Conveyor 26 is provided about as wide as the maximum sizepackage intended to be handled and guides 32 and 33 are mounted to befully adjustable in or out to adjust for package width. It will be notedhowever that front guide 32 requires but little adjustment since in aparticular machine the edge of the package P adjacent the front is linedup generally with the front sealing jaw in sealing section 25 on itsstraight line passage through the machine. The terms front and rear asused herein are related to the orientation of the film in sealingsection 25. The folded edge of the film is deemed to be toward the rear,the free edges toward the front.

Infeed conveyor 26 terminates above table 41 of package-insertingsection 24. Guides 32 and 33 extend above table 41 for an appreciabledistance with suflicient clearance from table 41 to permit passage ofinsertion arm 42 between the bottom of guides 32 and 33 and the top oftable 41. The package apparatus of the present invention operatesintermittently as will be explained below, and for this reason theinfeed conveyor-26 is provided with a motor and with a clutch/brakemechanism (not shown) to permit conveyor--26-tostartand-stop rapidly.The input end of conveyor 26 is adapted to receive the packages from aconveyor (not shown) associated with the package assembly operation.Preferably, but not necessarily, lead roller 27 is at a higher elevationthan trailing roller 28 so that conveyor 26 slants slightly towardstable 41.

The operating requirements of package infeed conveyor 26 are that 'itdeliver-the packages to be. overwrapped one by one onto,.table 41 of.thepackage-inserting section 24. Since package infeed conveyor 26operates intermittently its abilityQto-accomplish thisrequireme'ntdepends largely upon the rateand regularity of the delivery of packagesto it. Where 'thepackages' are fed'from acontinuously operating'conveyorat a sufficient volume it may be possible under'certain conditionstoform a continuous line of packages on in'feedco'nveyor 26 and toforcepackages off conveyor 26 onto table 41 even though conveyor 26 hasstoppedgWhen this is a possibility 'a' clamping mechanism (not'shown)isprovided on one "of the guides 32 or 33 to clampany-packagetherebetween and" to prevent its movement. Such clamping means whenprovided is so actuated that it becomes operative whenever infeedconveyor 26 is stopped and becomes inoperative whenever infeed conveyor26 is operating. More frequently it is merely necessary to separatesuccessive packages to insure that only one at a time reaches table 41of package inserting section 24. This is most easily accomplished byproviding an accelerator roll 36 at the end of infeed conveyor 26 beyondconveyor roller 28. Accelerator roll 36 is run at a substantially higherperipheral speed than infeed conveyor 26 and therefore speeds up thepackage contacting it separating that package from the next succeedingone.

The film unwind and inverting section indicated generally at 23comprises a film unwind stand 37 and a film inverting head 38. Filminverting head 38, which is a generally U-shaped member with horizontalarms, is located with one arm above and one arm below table 41 ofpackage-inserting section 24, and in normal configuration is oriented at45 to the path of travel of packages through packaging apparatus 21.

Film unwind stand 37 which is located to the rear of packaging apparatus21 (see also FIGS. 3, 4 and comprises two parallel rollers 43 and 44adapted to cradle a roll 45 of folded film F in such manner in thenormal set up that the axis of the roll 45 of film is parallel to thepath of travel of packages P through apparatus 21. Cradleroller 43 isprovided with two adjustable clamping collars 46 and 47 to adjust theaxial position of roll 45 of film F. v

It has been found desirable for smooth operation of the apparatus toprovide a motorized film unwind for two reasons. In the first place themotorized unwind provides tension-free film F to go over and through thefilm inverting head 38 where since friction is a function of webtension, the reduction in tension reduces friction and makes everythingwork easier. Secondly, it is much more difiicu lt to obtain good sealson a package if the film is under tension while the seal is being made.This is particu larly true in an L;type sealer incorporating a hot wireimpulse seal such as in the present apparatus because as the seal ismade, the film is cut and if there is tension in the film, the twopieces will tend to pull away fromthe seal area. This causes a short andunpredictable exposure of the film in the seal region to the heatsealing element and it also releases the pressure clamping the top andbottom webs of film together. In certain types of shrink film, the filmstarts to shrink so rapidly from the sealing heat that the top andbottom webs curl away from each other and do not fuse together unlessthey are properly clamped. T his problem is particularly serious in thecase of an L- type sealer such as the one incorporated in the presentapparatus where the transverse sealing jaw forms both the final seal onthe first package and afirst seal on the follow- "i'ng simultaneously,and where thefilmis'unwoundliypressingthe-succeedingpackageagainstthefirst seal because a poor seal inthe first seal area Will allow the pack- 5 age to break through withoutfeeding film, resulting in a inverting head 38.-Dancer roll 49 ismounted on dancer roll ,carrier 52 which in turn is pivoted at 53 to therear of unwind stand 37. As film F is pulled through "inverting"headf'38 by the passagejiof packages P :d'ance'r roll 49 is caused torise rotating dancer roll carrier 52 about pivot'53. At a predeterminedpoint the r'otation of. dancer determined level dancer rollcarrier 52-reactivates'limit switch 54 shutting off geanmotpr55. Preferably1the twoidler rolls 4'8' 'and-51' are at approximately the same level and theworking range of dancerroll 49 is, of course, be-

low the level of the idler rolls. Gear motor 55 is provided with areverse switch so that it may be run in either direction depending onwhich way the film in roll 45 has been wound. The 'folded edge of film-Fwill always .be to 'the right as shownin FIG. 1. For reasons that'willbe explained below means (not shown) are provided to adjust the verticalposition of idler rolls 48 and 51.

folding section 61 comprises a stand 62, vertical film roll holdingspindle 63 mounted on said stand and means 64 mounted on said spindlefor adjusting the elevation of a roll of film45. mounted on spindle 63.Film'F from roll 45 is passed over V-shaped folding head 65 and the twoedges of the film are directed toward the rear as seen in FIG. 6. Thetwo sides of the center-folded film are brought into face to facecontact upon passing through "horizontal squeeze rolls 66 and-"67.As'used in the context of this applicationthe term center-folded film isintended to include not only those instances where the fold is preciselyin the center, and the twoedges mate, but also those instances where thefold is not precisely in the center .and the two edges are somewhatoffset as in the caseof thehso-called l-foldedfi lm. In the case of a{folding head as shown in FIG. 6 the difference is based .on whether ornot the center line of the roll 45 of film F is lined up precisely withthe centerline of the folding head, or in other ,words whether or notadjusting means 64 is precisely locatedf 5 The-pre-folded, film frompre-folding section 61 is then passed over film unwind stand 37 which isaltered only to the extent of providing a pressure roller 68 to pressagainst-driven cradle roller 43 to maintain the film in frictionalcontact therewith. Pressure roller 68 is pivotally 0 mounted on arm 69which in turn is pivotally mounted at 71 to unwind stand 37. A spring 72may be provided to load pressure roller 68 to keep the film in contactwith cradle roll 43. From cradle roll 43 the film is passed over idlerroll 48 under dancer roll 49 and over idler rolls 65 51 to filminverting head 38 in the same manner as above.

inverting head 38 has parallel arms 75 and 76 both of .which extendhorizontally with the one oriented vertically above the other, and withlower arm 76 extending beneath table 41 of package inserting section 24.The portion 77 of the U-shaped member comprising film inverting head 75"38 connecting parallel arms 75 and 76 is preferably semicircular inshape and is located to the right rear relative to the other portions offilm inverting head 38. Preferably the normal to the angle at which thefilm inverting head 38 is oriented approximately bisects the anglebetween the axis of package travel through the machine and the axis ofthe film path from film unwind stand 37 to film inverting head 38. Mostconventiently, since it is easier to make things square, film unwindstand 37 is oriented such that the film passes at 90 to the axis ofpackage travel, and therefore the film inverting head 38 is normally setat an angle of about 45. Neither of these angles appears to beparticularly critical. The only basic requirement appears to be that thefolded film comes from the rear portion of the machine well out of thepath of the packages through the machine, and that the film invertinghead 38 be set at an angle the normal of which approximately bisects theangle between the two.

Film F is led from film unwinding stand 37 toward film inverting head 38with the folded edge toward the right (as in FIG. 1) and adjacent torounded portion 77 The film is preferably brought in at an elevationsuch that the web of film coming from the unwind is at the same level asthe center of the inverting head. This is accomplished by adjusting thevertical location of idler roll 51. Thus the distance the film has totravel around the head is exactly the same for the top web of film as itis for the bottom web of film, since the fold is located at the centerof curve portion 77, insuring that when the film comes off the invertinghead the top and bottom edges of the film will meet together under thefront sealing jaws. On the other hand if it is desired, for any reason,not to have the top and bottom edges meet either the top or bottom edgesmay be moved toward the front by merely displacing idler roll 51 aboveor below the center line position. The film is unfolded to the extentthat the free sides are extended above and below arms 75 and 76respectively in contact with the outer edges thereof with the inner sideof the film at the center fold portion being in contact with the outerside of rounded portion 77. The film is then tucked inside of filminverting head 38 and extended toward the left in the direction of thepath of travel of packages P therethrough. This turns the film insideout as shown in FIGS. 7 and 8 with the center fold parallel to the pathof travel of the packages toward the rear of apparatus 21 and the freeedges toward the front of apparatus 21.

In view of the path of travel of film F from film unwind stand 37 to theoutside of film inverting head 38 and back through the inside of filminverting head 38 toward sealing section 25, filmdnverting head is mostconveniently formed of a length of round stainless steel stock. Sincethe film comes in from the back on the outside and leaves toward theleft on the inside any type of fabrication could be used as long as thesurfaces actually contacting the film are sufficiently smooth androunded as required, and as long as the extremities of the structureextend beyond the width of the widest film to be used. Thus in the caseof the particular film inverting head 38 shown in FIG. 1, for example,arms 75 and 76 extend to the front left corner of package insertingsection 24 where they are joined to vertical post 78 which in turn isfastened to horizontal support member 79 upon which table 41 is mounted.A brace 81 may be provided from the midpoint of curved portion 77parallel to the path of travel of package P and the film F (frominverting head 38 to sealing section 25) to a bracket 82 mounted on theleft side of support member 79 beyond the edge of the widest arm 75.This leaves the front of inverting head 38 open and free of obstructionwhich is a great advantage when the machine is adapted for manualoperation. In this variation, the front end of upper arm is connected tobrace which in turn extends to bracket 82.

It will be understood, of course, that the terms horizontal and verticalas used herein refer to the mutual relationship of the parts to anarbitrary internal reference plane which, for example, could be taken asthe plane of the lower sealing jaws, and does not necessarily refer tothe floor or other external reference plane.

The use of center folded film and the horizontally extending U-shapedfilm inverting head has -a number of advantages. One is that theinverting head opens up the film uniformly and permits easy insertion ofpackages P therethrough as they are slid across table 41 of packageinserting section 24 which table extends into the film inverting head38. While it is desirable to use a low profile inverting head for lowprofile packages, and a high profile inverting head for high profilepackages, a wide range of package heights can be run through any givensize inverting head. Thus a 3" high head can be used for any packagesbetween A8" and 2 /2" high and a 4 /2" high inverting head will handlepackages between /2" and 4" high. This wide range means that relativelyfew changeover parts are required to handle a wide assortment of packagesizes which, of course, minimizes change-ov r time.

As pointed out above in describing the infeed section, the apparatus isnormally operated so that the front edge of the package is lined upgenerally with the front sealing jaw in sealing section 25. Thus widthadjustment is accomplished merely by moving film-inverting head 38 in orout so that rounded portion 77 just clears the rear edge of the package.As will be explained below, horizontal support means 79 is adapted toslide in and out relative to frame 31 to accomplish this. Whiletheoretically a single width of film could be used for all widths ofpackages, it is preferable, in order to avoid excess waste of film, tosubstitute rolls of a proper width when the width of a package ischanged.

Since, as will be explained below, the film is advanced by the packageitself and the package is pushed through the film inverting head 38 byinsertion arm 42 onto sealing section 25 no adjustment is necessary tocompensate for changes in the length of the package. In this manner thefilm is pulled through the film-inverting head. Since the film is fed tothe inverting head from the roll of folded film in such a manner thatthe fold is to the far right as viewed in FIG. 1 and the open edges ofthe film are to the far left, the film tracks over the inverting head insuch a manner that the fold stays at the curved portion of the invertinghead and the edges stay to the far left. In passing over the invertinghead, the film is turned inside out, providing an opening into which thepackage can be inserted; in fact, the film is actually Wrapped aroundthe package by placing the outside of the film against the package. Theangle of the inverting head is such that the folded portion of the filmtends to stay to the rear of the machine, as viewed in FIG. 1, and theopen edges tend to stay to the front and thus the film tends to beself-tracking and self-correcting. If for any reason the fold is offseton any package, the offset is corrected by the next two or threepackages. This is quite important in the L-type sealer since in order toform the front seal, the two edges of film must lay one over the otherin the seal region. Obviously, if one of the edges of film pulls backover the package, only one layer of film will lay under the sealing jawsand no seal will result.

Package-inserting section 24 comprises table 41 and reciprocal insertionarm 42. Table 41 extends from beneath the end of package infeed conveyor26 or accelerator roll 36 if one is provided through film inverting head38 to the leading edge of sealing section 25. Table 41 in extendingthrough inverting head 28 extends above lower arm 76 thereof withsufficient clearance therefrom to permit the free passage of the lowerportion of folded film F. Table 41 is mounted along its front edge onhorizontal sliding support member 79 which extends beneath the lower arm76 of film inverting head 38 and to which film inverting head 38 isattached. Support member 79 is mounted on main frame 31 in such manneras to be movable inwardly and outwardly at right angles to the path ofpackages through the apparatus. The front edge of sliding support member79 extends in a downwardly extending flange 83 to which horizontalsupport rods 90 are attached. Support rodsv-90 pass through cooperatingholes in the front of main frame member 81. The rear edge of supportmember 79 as shown, is provided with two horizontallyextending'rectangular tab'members 84 and 85 which rest on a cooperatinghorizontal surface of frame member 31. Tab members 84 and 85 are eachprovided with an internal longitudinally extending slot 86 and 87through which extends a fastening member 88 and 89 fastened to framemember 31. Adjustment for the width of packages is made by looseningfastening members 88 and '89, moving support member 79 backwardly andforwardly to the desired position (thus moving both table 41 and filminverting head 38) and retightening fastening members 88 and 89.

Insertion arm 42 is mounted on a carrier assembly which rides on linearball bearings on a guide rod inside cylinder housing 91 which, in turn,is mounted on the forward edge of support member 79. The cable from theair cylinder piston is fastened to this carrier and thus as the pistonmoves back and forth in the cylinder, the carrier is caused to move backand forth in the opposite direction on the guide rod, thus movinginsertion arm 42. The normal position for insertion arm 42 is at aposition beneath the discharge end of infeed conveyor 26. As the packageP drops from conveyor 26 it passes over insertion arm 42 and strikesactuating switch 92 mounted near the top of table 41. Switch 92 uponbeing actuated causes a solenoid to operate which in turn admits air tothe air cylinder 91. The particular type of cylinder that has been foundto be most useful is one provided with a pulley at both ends and with acable passing around both pulleys and with both ends attached to apiston within the cylinder. As the piston moves from one end of thecylinder to the other, the cable moves in the opposite direction alongthe outside of the cylinder. This cable is fastened to insertion arm 42which is guided by linear ball bearings on a hardened steel rod. Uponactuation insertion arm 42 moves from right to left across table 41contacting the rear of package P which has been deposited thereon frominfeed conveyor 26 pushing package P across table 41 through filminverting head 38 onto table 101 in sealing section 25. As the forwardedge of package P moves across the transverse sealing member of sealingsection 25 it contacts the transverse seal in film F formed by the priorsealing operation. This, together with the folded edge, forms two sidesof a pouch surrounding package P. As package P continues to move forwardinto sealing section 25 pushed by insertion arm 42 it drags film -Falong with it. The stroke of insertion arm 42 is adjusted so that itdeposits package P entirely within sealing section 25 just beyond thetransverse sealing jaws. Insertion arm 42 is offset as indicated inorder to clear mounting post 78 of film inverting head 38, although theedge that contacts package P is transverse to the path of travel ofpackage P. At the forward end of the stroke of insertion arm 42 a limitswitch (not shown) is contacted which causes the air supply to thecylinder to be reversed, returning insertion arm 42 to its initialposition beneath the end of infeed conveyor 26. As insertion arm 42moves away from sealing section 25 it contacts a sec- 0nd limit switch(not shown) which initiates the sealing described and claimed in mycopending U.S. patent application Ser. No. 626,117, filed Mar. 27, 1967entitled Apparatus for Heat Sealing Plastic Film. Reference to mycopending application is specifically made for details of theconstruction and operation of the sealing section 25.

In essence sealing section 25 comprises an upper and lower transversesealing jaw 93 and 94 and an upper and lower longitudinal sealing jaw 95and 96. The upper sealing jaws 93 and 95 are provided with heated meansfor forming seals; are joined together to form an L- shaped structure toform a continuous L-shaped seal; and are pivotally mounted as indicatedat 97 and 98 at their free ends along a diagonal pivot axis forreciprocal motion about this axis. The upper sealing jaws are pivoteddownwardly into contact with the lower sealing jaws during the sealingoperation and are raised to an elevated position between sealing,operations. Lower sealing jaws 94 and 96 are mounted on frame 31 so thatthe sealing surface is at sufficiently lower leve1=' than table 41 -ofpackage insertion section 24, to permit easy passage of the lower levelof film F. Preferably the sealingjaws'are of the so-called impulse type.designed not only to form a seal between the two layers of film, butalso to sever the film along the middle of the seal leaving a seal onboth sides of the severed portion.

Within the area limited by the inner edges of lower sealing jaws 94 and96 there is provided a sealing table 101. Table 101 is a conveyorcomprising a belt 102 mounted over two horizontal transverse rollers 103and 104 which are mounted on frame 105 (see FIG. 10). Table 101 isadjustable vertically relative to main frame 31, the mounting for frame105 comprising three jack.

. 101 up or down as the case may be. I

In use the height of sealing table 101 is adjusted carefully so that thesealing jaws are located at the mid-point 'of' the package. This isquite important in the case of folded film since the distance that thefilm travels around the bottom of the. package should always be equal tothe distance that the film travels around the top of the package whenthe film is joined at the fold at the rear of the package. Since thisdistance should also be equal left and right as well as front to rearthe seal should be at the center of the package.

Belt 102 of sealing table 101 is provided with a drive means indicatedby sprocket 112 and drive chain 113 and by sprocket 114, on pulley 103.After the sealing arms open the drive means for belt 102 is actuatedthrough a timer causing the belt to move for a predetermined length oftime suflicient to cause the package to move off of table 101 to thenext station. Upon the expiration of the predetermined time belt 102 isstopped and remains stationary until after the next succeeding packagehas been received thereon and the sealing operation has been completedon this next succeeding package. t

A guide member 115 mounted on bracket 116 which in turn is mounted onframe 105 is provided to keep the package in the proper positionrelative to the sealing jaws as a package P is introduced onto table 101by the action of insertion arm 42. As shown the. guide member 115 ismounted'on 'two horizontal rods 117 and 118 which in turn pass throughholders 119 and 120 :in bracket 116. Guide member 115 is thus easilyadjustable to accomr'nodate packages of different widths. Althoughnot'shown the guide member 115 can be provided with a stop member whichextends into the path of travel of package P to prevent overtravel ofthe package. It is anticipated that as thespeed of the machine isincreased the momentum of the package may be such as it is pushed ontosealing table 101 by insertion arm 42 the package will be thrown beyondthe desired sealing position. A reciprocal stop member in guide member115 would prevent this. Such a stop could be connected to the controlsfor the drive means of belt 102 in such manner that the stop memberwould be retracted and inoperative during the period that the belt wasoperating and would be extended and operative while the belt is stopped.

Upon being discharged from sealing table 101 the package P is normallymoved onto a conveyor belt of a heated shrink tunnel for the purpose ofshrinking film as into close contact with package P. The shrink tunnelnot being part of the present invention is not shown, but a suitablesuch tunnel is disclosed and claimed in my prior United States LettersPat. No. 3,312,811, dated Apr. 4, 1967 entitled Shrink Tunnel. While notreally necessary, it has been found that a section of roller conveyor123 mounted on frame 105 helps provide a smooth transfer from theconveyor of table 101 to the conveyor of the shrink tunnel.

A scrap removal system should be provided to remove the selvage edge offilm that is cut off from the front edge of the package by the front(longitudinal) sealing jaws 95 and 96. Unless this selvage edge isremoved it will lay in the region of the seal, tend to reweld to otherpackages and eventually make it impossible to obtain a good seal. Thebest technique for removing the selvage edge appears to be the use of avacuum hose as indicated at 125 mounted with its opening adjacent theouter edge of lower longitudinal sealing jaws 96 at a positionsufficiently removed from the lower transverse sealing jaw 94 that iswell beyond the extent of any package coming onto sealing section 25.Several types of suction blowers and shop vacuum cleaners have been usedsuccessfully. The important thing is to regulate the vacuum of the hoseso that a sufficient pull is available to strip the film from the jawsof the sealer where the film has a slight tendency to stick and yet notso much as to pull film from the unwind mechanism or to pull the filmout of the seal area. 1

A second advantage for using a vacuum source for a scrap removal systemis that this keeps a constant uniform tension on the front edges of thefilm. This causes the free edges of the film to move toward the front ofthe inverting head tending to keep the film smooth and reasonably tautthereon and making the tracking of the film through the inverting headmore certain.

To summarize the operation of the packaging apparatus packages P whichare to be overwrapped with a conveyor 26. Assuming the packagingapparatus 21 to be empty, infeed conveyor 26 would be in operation andwould move package P onto table 41 of package insertion section 24 wherepackage P hits switch 92. The action of switch 92 stops infeed conveyor26 and actuates a relay that actuates package insertion arm 42 which inits normal position is maintained beneath the discharge of infeedconveyor 26. When the sealing arm of sealing section 25 is in its raisedposition package insertion arm 42 moves across table 41 pushing thepackage P before it, through film inverting head 38 and onto table 101of sealing section 25. At the end of its stroke the direction of arm isreversed and as it passes out of sealing section 25 it actuates a limitswitch that actuates the sealing section. As package insertion arm 42returns to its normal position beneath the discharge of conveyor 26another limit switch is actuated which restarts conveyor 26 permittingthe next succeeding package to be deposited onto table 41 againactuating switch 92. An interlock arrangement for package insertion arm42 insures that arm 42 can move forward only when the sealing jaws arein their raised position. Thus since table 101 of sealing section 25comprises a discharge conveyor which is turned on for a predeterminedtime .50 shrink film are deposited one by one on package infeed as soonas the sealing jaw separates upon-the completion of the seal theoperation of the apparatus is entirely automatic.

While the machine itselfhas been described as one which is entirelyautomatic in operation, it is obvious that inverting head 38 couldeasily well be used manually to great advantage. Packages could merelybe inserted by hand through inverting head 38- onto sealing area 25.Since the inverting head keeps the film open and centered this can bedone much more rapidly and much more easily than in the conventionalmachines where the film has to be separated by hand or by other meansbefore the article can be inserted. Obviously, if only manual operationis desired any L-type sealer can be provided with just the film unwindand inverting section 23 which comprises film unwind stand 37 and filminverting head 38. As mentioned above, where the inverting head 38 isintended for use manually, the variation shown in FIG. 8 wherein thefront of the inverting head is en tirely open is preferred. The use ofthe motorized film feed is desirable to avoid excess film tension.

Even in the case of the automatic machine as described it is sometimesnecessary with certain articles to be wrapped to feed these articlesmanually because the articles for one reason or 'another are notamenable to automatic feed. Since air cylinder housing 91 extendsupwardly at the front of table 41 and would be in the way were themachine to be used for manual operation, making the feeding of articlesby hand somewhat awkward, it is preferable to provide a substitutehorizontal sliding support member 79 which is provided only with table41 and film inverting head 38. Where it is intended to use both manualand automatic package inserting sections 24 support means can beprovided immediately under section 24 in frame 31 to store theparticular section which, at that moment, is not being used andsufficiently long leads can be provided for the connections 'to the aircylinder in housing 91, and to the several limit switches that theseneed not be disconnected every .time the automatic section 24 is movedinto and out of place.

I claim: 1. In an apparatus for wrapping packages in a thermoplasticfilm having a film supply means wherein thermoplastic film is suppliedas an elongated length folded back upon itself along a longitudinal axisto form a top and a bottom web portion overlying one another in closejuxtaposition one to the other and. is directed into the apparatus alonga horizontal path with the folded edge on one side and the free edges onthe other, and

a film sealing means having at least an intermittently operatedtransverse sealing means for sealing said folded film transverselybetween said folded edge and said free edges a film inverting headlocated between said film supply means and said film sealing means inthe path of package flow through said apparatus in such a manner thatthe fold line in said folded film may be passed through the center lineof the inverting head, and that the film is redirected and turned insideout in passing over and through said inverting head, said inverting headproviding an opening into which a package may beinserted between theconnected webs of said film said inverting head comprising a pair ofspaced arms operably associated at one end, said arms intersecting saidpath of package flow with one arm extending above and the otherextending below said path of package flow and being directed at an angleboth to the path of package flow and to the path of film travel fromsaid supply means to said head with the operably associated end of saidhead sub- 1 stantially aligned with the path of the folded edge of saidfilm whereby after a first transverse seal has been made in said lengthof film, the passage of a package along said path of package flowthrough said inverting head 12 head, said inverting head providing anopening into which a package may be inserted between the connected websof said film said inverting head comprising a pair of spaced armsoperably associated at one end, said arms intersectand across saidtransverse sealing means draws 5 ing said path of package flow with onearm extendenough film from said film supply means over and ing above andthe other extending below said path through said inverting head tosurround said package. of package flow and being directed at an angleboth 2. In an apparatus for wrapping packages in a thermoto the path ofpackage flow and to the path of film plastic film travel from saidsupply means to said head with having a film supply means whereinthermoplastic film the operably associated'end of said headsubstantially is supplied as an elongated length folded back uponaligned with the path of the folded edge of said itself along alongitudinal axis to form a top and a film bottom web portion overlyingone another in close the path of said film travel to said head beingsubstanjuxtaposition one to the other and is directed into the tially atright angles to the path of said package fiow, apparatus along ahorizontal path with the folded and edge on one side and the free edgeson the other, the said head being set at an angle of about 457 to andboth said path of package flow and said path of film a film-sealingmeans having at least an intermittently travel operated transversesealing means for sealing said the film inverting head being mounted tomove in a folded film transversely between said folded edge anddirection normal to said path of package flow wheresaid free edges byadjustment for packages of varying width may a film inverting headlocated between said film supply be accomplished merely by moving saidfilm invertmeans and said film sealing means in the path of ng headpackage fiow through said apparatus in such a whereby after a firsttransverse seal has been made in manner that the fold line in saidfolded film may said length of film, the passage of a package along bepassed through the center line of the inverting said path of packageflow through said inverting head head, and that the film is redirectedand turned inand across said transverse sealing means draws side out inpassing over and through said inverting enough film from said filmsupply means over and head, said inverting head providing an openinginto through said inverting head to surround said'packwhich a packagemay be inserted between the conage. nected webs of said film 4. In anapparatus for wrapping packages in a thermosaid inverting headcomprising a pair of spaced arms plastic film operably associated at oneend, said arms intersecthaving a film supply means wherein thermoplasticfilm ing said path of package flow with one arm extendis supplied as anelongated length folded back upon ing above and the other extendingbelow said path itself along a longitudinal axis to form a top and a ofpackage flow and being directed at an angle both bottom web portionoverlying, one another in close to the path of package flow and to thepath of film juxtaposition one to the other and is directed into travelfrom said supply means to said head with the apparatus along ahorizontal path with the folded the operably associated end of said headsubstantially 40 edge on one side and the free edges on the other,aligned with the path of the folded edge of said and I film a filmsealing means having at least an intermittently the path of said filmtravel to said head being substanoperated transverse sealing means forsealing-said ally at right angles to the path of said package flow,folded film transversely between said folded edge and and said freeedges Y the said head being set at an angle of about to 45 a filminverting head located between said film supply bo h said path ofpackage flow and said path of film means and said film sealing means inthe path of travel package flow through said apparatus in such a mannerwhereby after a first transverse seal has been made in that the foldline in Said folded film y be Passed said length of film, the passage ofa package along through the center line of the inverting head, "and sapath of package flow through said inverting head that the film isredirected and turned inside out in and across said transverse sealingmeans draws passing over and through said inverting hea Said enough filmfrom said film supply mean over and inverting head providing an openinginto which a through said inverting head to surround said packpackagemay be inserted between the connected webs age. of said film v 3. In anapparatus for wrapping packages in a ther osaid inverting headcomprising a pair of spaced arms plastic film operably, associated atone end and oriented substanhaving a film supply means whereinthermoplastic fil tially parallel one above the other, said arms interissupplied as an elongated length folded back upon secting aid path ofpackage flow with one arm exitself along a longitudinal axis to form atop and a tending above and the other eXteIldi'Il'g below a bottom webportion overlying one another in close P of Ptltlkage flow andbeingdirected tit angle juxtaposition one to the other and is directedinto the both to the P Of Package and t0 the P apparatus along ahorizontal path with the folded 0f film v l m said pp y means to -heaedge on one side and the free edges on th oth with the operablyassociated end of said head suband stantially aligned with the path ofthe folded edge a film-sealing means having at least an intermittentlyof said film v operated transverse sealing means for sealing saidwhereby after a first transverse 8631 has been made folded filmtransversely between said folded edge and in Said l g h f m, th passageof (l -pa kage along said free edges said path of package flow throughsaid inverting head a film inverting head located between said filmsupply and across Said transverse Sealing II'leflIlS draws means andsaid film sealing means in the path of enough film from Said film pp ymeans CV61 and package flow through said apparatus in such a throughsaid inverting head to surround said packunanner that the fold line insaid folded film may age. 7 i be passed through the center line of theinverting 5. In an apparatus for wrapping packages in-a thermohead, andthat the film is redirected and turned inplastic film 7 side out inpassing over and through said inverting having a film supply meanswherein thermoplastic film is supplied as an elongated length foldedback upon itself along a longitudinal axis to form a top and a bottomweb portion overlying one another in close juxtaposition one to theother and is directed into the apparatus along a horizontal path withthe folded edge on one side and the free edges on the other, and

a film sealing means having at least an intermittently operatedtransverse sealing means for sealing said folded film transverselybetween said folded edge and said free edges a film inverting headlocated between said film supply means and said film sealing means inthe path of package flow through said apparatus in such a manner thatthe fold line in said folded film may be passed through the center lineof the inverting head, and that the film is redirected and turned insideout in passing over and through said inverting head, said inverting headproviding an opening into which a package may be inserted between theconnected webs of said film said inverting head comprising a pair ofspaced arms operably associated at one end, said arms intersecting saidpath of package flow with one arm extending above and the otherextending below said path of package flow and being directed at an angleboth to the path of package flow and to the path of film travel fromsaid supply means to said head with the operably associated end of saidhead substantially aligned with the path of the folded edge of said filmthe path of package flow including a package support means which extendsthrough said film inverting head whereby after a first transverse sealhas been made in said length of film, the passage of a package alongsaid path of package flow through said inverting head and across saidtransverse sealing means draws enough film from said film supply meansover and through said inverting head to surround said package.

6. In an apparatus for wrapping packages in a thermoplastic film havinga film supply means wherein thermoplastic film is supplied as anelongated length folded back upon itself along a longitudinal axis toform a top and a bottom web portion overlying one another in closejuxtaposition one to the other and is directed into the apparatus alonga horizontal path with the folded edge on one side and the free edges onthe other, and

a film sealing means having at least an intermittently operatedtransverse sealing means for sealing said folded film transverselybetween said folded edge and said free edges a film inverting headlocated between said film supply means and said film sealing means inthe path of package flow through said apparatus in such a manner thatthe fold line in said folded film may be passed through the center lineof the inverting head, and that the film is redirected and turned insideout in passing over and through said inverting head, said inverting headproviding an opening into which a package may be inserted between theconnected webs of said film said inverting head comprising a pair ofspaced arms operably associated at one end, said arms intersecting saidpath of package flow with one arm extending above and the otherextending below said path of package flow and being directed at an angleboth to the path of package flow and to the path of film travel fromsaid supply means to said head with the operably associated end of saidhead substantially aligned with the path of the folded edge of said filmthe path of package flow including a package support means which extendsthrough said film inverting head and wherein automatic means areprovided for feeding packages one by one onto and across said supportmeans through said inverting head across said transverse sealing meanswhereby after a first transverse seal has been made in said length offilm, the passage of a package along said path of package flow throughsaid inverting head and across said transverse sealing means drawsenough film from said film supply means over and through said invertinghead to surround said package.

7. In an apparatus for wrapping packages in a thermoplastic film havinga film supply means wherein thermoplastic film is supplied as anelongated length folded back upon itself along a longitudinal axis toform a top and a bottom web portion overlying one another in closejuxtaposition one to the other and is directed into the apparatus alonga horizontal path with the folded edge on one side and the free edges onthe other, and

a film sealing means having an intermittently operated sealing means forsealing said folded film both transversely between said folded edge andsaid free edges and longitudinally along said free edges a filminverting head located between said film supply means and said filmsealing means in the path of package flow through said apparatus in sucha manner that the fold line in said folded film may be passed throughthe center line of the inverting head, and that the film is redirectedand turned inside out in passing over and through said inverting head,said inverting head providing an opening into which a package may beinserted between the connected webs of said film said inverting headcomprising a pair of spaced arms operably associated at one end, saidarms intersecting said path of package flow with one arm extending aboveand the other extending below said path of package flow and beingdirected at an angle both to the path of package flow and to the path offilm travel from said supply means to said head with the operablyassociated end of said head substantialliyi aligned with the path of thefolded edge of said whereby after a first transverse seal has been madein said length of film the passage of a package along said path ofpackage flow through said inverting head and across said transversesealing means draws enough film from said film supply means over andthrough said inverting head to surround said package.

References Cited UNITED STATES PATENTS 3,035,381 5/1962 Hosso 53-373X3,420,035 1/1969 Deans et a1. 5182 3,427,781 2/ 1969 Kral 53182X TRAVISS. MCGEHEE, Primary Examiner E. F. DESMOND', Assistant Examiner US. Cl.X.R.

